JP4479744B2 - Flow measuring device - Google Patents

Flow measuring device Download PDF

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JP4479744B2
JP4479744B2 JP2007118992A JP2007118992A JP4479744B2 JP 4479744 B2 JP4479744 B2 JP 4479744B2 JP 2007118992 A JP2007118992 A JP 2007118992A JP 2007118992 A JP2007118992 A JP 2007118992A JP 4479744 B2 JP4479744 B2 JP 4479744B2
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detection
resistor
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JP2008275427A (en
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順三 山口
泰 河野
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Denso Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements

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  • General Physics & Mathematics (AREA)
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Description

本発明は、空気の流量を測定する流量測定装置に関するものであり、特に内燃機関に吸入される空気の流量を測定するのに好適な流量測定装置に関する。   The present invention relates to a flow rate measuring device for measuring the flow rate of air, and more particularly to a flow rate measuring device suitable for measuring the flow rate of air taken into an internal combustion engine.

従来より、流量測定装置１００には、図４に示すように、空気流路に空気の流れと略平行な平面状に設けられる絶縁膜１０１と、絶縁膜１０１の表面１０２に設けられて通電により発熱する発熱抵抗１０３と、表面１０２で発熱抵抗１０３の上、下流側に設けられ、温度に応じて電気抵抗が変化する上、下流側検出抵抗１０４、１０５とを備え、上、下流側検出抵抗１０４、１０５による検出差分に基づいて、空気流路を流れる空気の流量を測定するものが公知である（例えば、特許文献１参照）。   Conventionally, as shown in FIG. 4, the flow measuring device 100 is provided with an insulating film 101 provided in a plane substantially parallel to the air flow in an air flow path, and a surface 102 of the insulating film 101 provided by energization. A heating resistor 103 that generates heat, and is provided on the downstream side of the heating resistor 103 on the surface 102. The electrical resistance changes according to the temperature, and further includes downstream detection resistors 104 and 105. A device that measures the flow rate of air flowing through an air flow path based on the detection difference between 104 and 105 is known (see, for example, Patent Document 1).

すなわち、流量測定装置１００によれば、絶縁膜１０１の表面１０２上で上、下流側検出抵抗１０４、１０５で挟まれて区画される領域が検出差分を検出するための検出領域１０８をなしている。そして、発熱抵抗１０３により形成される発熱領域１０９が検出領域１０８を加熱することにより、検出領域１０８において空気の流れる方向に温度分布が生じ、この温度分布に応じた検出差分が検出されて流量の測定に利用される。このため、発熱領域１０９から検出領域１０８に与えられる熱量の内、検出領域１０８の加熱、つまり温度分布の形成に利用される割合が高いほど、流量検出感度が高く検出誤差も小さくなるものと考えられる。   That is, according to the flow rate measuring device 100, the region that is divided on the surface 102 of the insulating film 101 and sandwiched between the downstream detection resistors 104 and 105 forms the detection region 108 for detecting the detection difference. . Then, the heat generation area 109 formed by the heat generation resistor 103 heats the detection area 108, so that a temperature distribution is generated in the direction of air flow in the detection area 108, and a detection difference corresponding to this temperature distribution is detected to detect the flow rate. Used for measurement. For this reason, it is considered that the higher the proportion of the amount of heat given from the heat generation area 109 to the detection area 108 is used for heating the detection area 108, that is, for forming the temperature distribution, the higher the flow rate detection sensitivity and the smaller the detection error. It is done.

ところで、発熱領域１０９から検出領域１０８に与えられる熱量は、全量が検出領域１０８の加熱に利用されるのではなく、一部は、検出領域１０８の加熱に有効に利用されず放熱されてしまう。特に、発熱抵抗１０３の端子１１０、１１１は、直接的に発熱抵抗１０３に接続して熱伝導を受けやすく、さらに伝熱抵抗も小さいので、発熱領域１０９からの大きな放熱先となっている。   By the way, the amount of heat given from the heat generation area 109 to the detection area 108 is not entirely used for heating the detection area 108, but a part of it is dissipated without being effectively used for heating the detection area 108. In particular, the terminals 110 and 111 of the heat generating resistor 103 are directly connected to the heat generating resistor 103 and easily receive heat conduction, and the heat transfer resistance is small, so that they are large heat radiation destinations from the heat generating region 109.

そこで、流量測定装置１００では、端子１１０、１１１に接続する発熱抵抗１０３の電位端１１４、１１５を検出領域１０８の一端縁１１６に配し、発熱領域１０９から端子１１０、１１１への放熱を検出領域１０８の一端側でのみ行う。これにより、検出領域１０８の一端縁１１６および他端縁１１７の両方に電位端１１４、１１５を一方ずつ配して発熱領域１０９から端子１１０、１１１への放熱を検出領域１０８の一端側および他端側の両方で行う場合よりも、端子１１０、１１１への放熱量を少なくすることができる。
しかし、電位端１１４、１１５を一端縁１１６のみに配しても、電位端１１４、１１５から端子１１０、１１１への放熱量は相変わらず多いものと考えられ、さらなる流量検出感度の向上策が求められている。
特開２０００−１９３５０５号公報 Therefore, in the flow measuring device 100, the potential ends 114 and 115 of the heating resistor 103 connected to the terminals 110 and 111 are arranged at one end edge 116 of the detection region 108, and the heat radiation from the heating region 109 to the terminals 110 and 111 is detected in the detection region. This is done only at one end of 108. As a result, the potential ends 114 and 115 are arranged one by one on both the one end edge 116 and the other end edge 117 of the detection region 108 so as to dissipate heat from the heat generation region 109 to the terminals 110 and 111. The amount of heat radiation to the terminals 110 and 111 can be reduced as compared with the case where both are performed on both sides.
However, even if the potential ends 114 and 115 are arranged only at the one end edge 116, it is considered that the amount of heat released from the potential ends 114 and 115 to the terminals 110 and 111 is still large, and further measures for improving the flow rate detection sensitivity are required. ing.
JP 2000-193505 A

本発明は上記の問題点を解決するためになされたものであり、その目的は、発熱抵抗の上、下流側に設けられる上、下流側検出抵抗の検出差分に基づいて、空気の流量を測定する流量測定装置において、流量検出感度を向上させることにある。   The present invention has been made in order to solve the above-described problems, and its purpose is to measure the air flow rate based on the detection difference of the downstream detection resistor, in addition to being provided on the downstream side of the heating resistor. An object of the present invention is to improve flow rate detection sensitivity in the flow rate measuring device.

〔請求項１の手段〕
請求項１に記載の流量測定装置は、空気流路に空気の流れと略平行な平面状に設けられる絶縁膜と、絶縁膜の表面に設けられて通電により発熱する発熱抵抗と、絶縁膜の表面で発熱抵抗の上、下流側に設けられ、温度に応じて電気抵抗が変化する上、下流側検出抵抗とを備える。そして、流量測定装置は、上、下流側検出抵抗の検出差分に基づいて、空気流路を流れる空気の流量を測定する。 [Means of Claim 1]
According to a first aspect of the present invention, there is provided a flow rate measuring apparatus comprising: an insulating film provided in a plane substantially parallel to an air flow in an air flow path; a heating resistor provided on a surface of the insulating film and generating heat when energized; Provided on the surface on the downstream side of the heating resistor, the electrical resistance changes according to the temperature, and further includes a downstream detection resistor. And a flow measuring device measures the flow volume of the air which flows through an air flow path based on the detection difference of an upper and downstream detection resistance.

また、絶縁膜の表面に平行で、かつ空気の流れと直交する方向を長手方向と定義すると、上、下流側検出抵抗は、長手方向に互いに平行に設けられ、絶縁膜の表面上で上、下流側検出抵抗で挟まれて区画される領域は、検出差分を検出するための検出領域をなしている。そして、上流側検出抵抗および下流側検出抵抗の電位端が、検出領域の長手方向の両端縁から引き出されている。また、発熱抵抗は、絶縁膜の表面上に検出領域を加熱するための発熱領域を形成し、発熱領域の長手方向の一端縁のみに、発熱抵抗の電位端が配されている。そして、発熱領域の長手方向の一端縁が、検出領域の長手方向の一端縁よりも一端側に突出している。 Further, when the direction parallel to the surface of the insulating film and perpendicular to the air flow is defined as the longitudinal direction, the upstream and downstream detection resistors are provided in parallel to each other in the longitudinal direction, and on the surface of the insulating film, An area that is sandwiched and divided by the downstream detection resistor forms a detection area for detecting a detection difference. The potential ends of the upstream detection resistor and the downstream detection resistor are drawn from both end edges in the longitudinal direction of the detection region. Further, the heating resistor forms a heating region for heating the detection region on the surface of the insulating film, and the potential end of the heating resistor is disposed only at one end edge in the longitudinal direction of the heating region. And the one end edge of the longitudinal direction of a heat_generation | fever area | region protrudes in the one end side rather than the one end edge of the longitudinal direction of a detection area | region.

また、発熱抵抗の上流側と下流側との温度差が最高になる長手方向の位置が、検出領域の長手方向の中央付近に位置し、発熱領域の長手方向の一端縁と他端縁との距離Ｌ０、および、上、下流側検出抵抗の長手方向の長さの１／２の位置と発熱領域の長手方向の一端縁との距離Ｌ１は、以下の相関式を満たす。In addition, the longitudinal position where the temperature difference between the upstream side and the downstream side of the heating resistor is the highest is located near the center of the longitudinal direction of the detection region, and the longitudinal edge of the heating region is between one end edge and the other end edge. The distance L0 and the distance L1 between the longitudinal position of the upper and downstream detection resistors in the longitudinal direction and one end edge in the longitudinal direction of the heat generation region satisfy the following correlation equation.
〔数式１〕５４／１００≦Ｌ１／Ｌ０≦８１／１００[Formula 1] 54/100 ≦ L1 / L0 ≦ 81/100

発熱抵抗の電位端近傍では、端子への放熱が著しいため昇温が不十分になり、空気の流れ方向における温度分布が明確に形成されない。そこで、発熱抵抗の電位端が配される発熱領域の一端縁を検出領域の一端縁よりも長手方向の一端側に突出させることにより、発熱領域の内で温度分布の形成が不明確な電位端近傍を検出領域から除外する。これにより、発熱領域の内で温度分布の形成が明確な領域のみを検出領域に含ませることができるので、流量検出感度を高めることができる。 In the vicinity of the potential end of the heat generation resistor, the temperature is not sufficiently raised because heat is radiated to the terminals, and the temperature distribution in the air flow direction is not clearly formed. Therefore, by projecting one end edge of the heat generating region where the potential end of the heat generating resistor is disposed to one end side in the longitudinal direction from the one end edge of the detection region, the potential end where the temperature distribution is unclear in the heat generating region. The neighborhood is excluded from the detection area. Thus, only the region where the temperature distribution is clearly formed in the heat generation region can be included in the detection region, so that the flow rate detection sensitivity can be increased .

また、数式１を満たすように発熱領域と検出領域とを設ければ、上、下流側検出抵抗の検出差分に基づいて算出される長手方向の平均温度差を５０℃以上にすることができる。このため、流量検出感度を確実に高めることができる。 Further, if the heat generation area and the detection area are provided so as to satisfy Formula 1, the average temperature difference in the longitudinal direction calculated based on the detection difference of the upper and lower detection resistances can be set to 50 ° C. or more. For this reason, the flow rate detection sensitivity can be reliably increased.

〔請求項２の手段〕
請求項２に記載の流量測定装置によれば、発熱抵抗の上流側と下流側との温度差が最高になる長手方向の位置と発熱領域の長手方向の一端縁との距離Ｌ２は、距離Ｌ１と同一である。
数式１を満たす距離Ｌ１を上記の距離Ｌ２と同一となるように発熱領域と検出領域とを設ければ、上、下流側検出抵抗の検出差分に基づいて算出される長手方向の平均温度差を最大値に略一致させることができる。このため、流量検出感度を最大限に高めることができる。 [Means of claim 2 ]
According to the flow rate measuring apparatus of the second aspect , the distance L2 between the longitudinal position where the temperature difference between the upstream side and the downstream side of the heating resistor becomes the maximum and one end edge in the longitudinal direction of the heating region is the distance L1. Is the same.
If the heat generation area and the detection area are provided so that the distance L1 satisfying Equation 1 is equal to the distance L2, the average temperature difference in the longitudinal direction calculated based on the detection difference of the upper and downstream detection resistances can be obtained. The maximum value can be substantially matched. For this reason, the flow rate detection sensitivity can be maximized .

最良の形態１の流量測定装置は、空気流路に空気の流れと略平行な平面状に設けられる絶縁膜と、絶縁膜の表面に設けられて通電により発熱する発熱抵抗と、絶縁膜の表面で発熱抵抗の上、下流側に設けられ、温度に応じて電気抵抗が変化する上、下流側検出抵抗とを備える。そして、流量測定装置は、上、下流側検出抵抗の検出差分に基づいて、空気流路を流れる空気の流量を測定する。   The flow measuring device of the best mode 1 includes an insulating film provided in a plane substantially parallel to an air flow in an air flow path, a heating resistor provided on the surface of the insulating film and generating heat by energization, and the surface of the insulating film And provided on the downstream side of the heat generating resistor, the electrical resistance changes according to the temperature, and further includes a downstream detection resistor. And a flow measuring device measures the flow volume of the air which flows through an air flow path based on the detection difference of an upper and downstream detection resistance.

また、絶縁膜の表面に平行で、かつ空気の流れと直交する方向を長手方向と定義すると、上、下流側検出抵抗は、長手方向に互いに平行に設けられ、絶縁膜の表面上で上、下流側検出抵抗で挟まれて区画される領域は、検出差分を検出するための検出領域をなしている。そして、上流側検出抵抗および下流側検出抵抗の電位端が、検出領域の長手方向の両端縁から引き出されている。また、発熱抵抗は、絶縁膜の表面上に検出領域を加熱するための発熱領域を形成し、発熱領域の長手方向の一端縁のみに、発熱抵抗の電位端が配されている。そして、発熱領域の長手方向の一端縁が、検出領域の長手方向の一端縁よりも一端側に突出している。 Further, when the direction parallel to the surface of the insulating film and perpendicular to the air flow is defined as the longitudinal direction, the upstream and downstream detection resistors are provided in parallel to each other in the longitudinal direction, and on the surface of the insulating film, An area that is sandwiched and divided by the downstream detection resistor forms a detection area for detecting a detection difference. The potential ends of the upstream detection resistor and the downstream detection resistor are drawn from both end edges in the longitudinal direction of the detection region. Further, the heating resistor forms a heating region for heating the detection region on the surface of the insulating film, and the potential end of the heating resistor is disposed only at one end edge in the longitudinal direction of the heating region. And the one end edge of the longitudinal direction of a heat_generation | fever area | region protrudes in the one end side rather than the one end edge of the longitudinal direction of a detection area | region.

また、発熱領域の長手方向の一端縁と他端縁との距離Ｌ０、および、上、下流側検出抵抗の長手方向の長さの１／２の位置と発熱領域の長手方向の一端縁との距離Ｌ１は、数式１を満たす。
そして、発熱抵抗の上流側と下流側との温度差が最高になる長手方向の位置と発熱領域の長手方向の一端縁との距離Ｌ２は、距離Ｌ１と同一である。 In addition, the distance L0 between the one end edge and the other end edge in the longitudinal direction of the heat generation area, and the position of 1/2 of the longitudinal length of the upper and downstream detection resistors and the one end edge in the longitudinal direction of the heat generation area The distance L1 satisfies Formula 1.
The distance L2 between the longitudinal position where the temperature difference between the upstream side and the downstream side of the heating resistor becomes the highest and one end edge in the longitudinal direction of the heating area is the same as the distance L1.

〔実施例１の構成〕
実施例１の流量測定装置１の構成を、図１を用いて説明する。流量測定装置１は、例えば、内燃機関に吸入される空気の流量を測定するために用いられる。 [Configuration of Example 1]
The configuration of the flow rate measuring device 1 according to the first embodiment will be described with reference to FIG. The flow rate measuring device 1 is used, for example, to measure the flow rate of air taken into an internal combustion engine.

流量測定装置１は、空気流路に空気の流れと略平行な平面状に設けられる絶縁膜２と、絶縁膜２の表面３に設けられて通電により発熱する発熱抵抗４と、表面３で発熱抵抗４の上、下流側に設けられ、温度に応じて電気抵抗が変化する上、下流側検出抵抗５、６とを備え、上、下流側検出抵抗５、６による検出差分に基づいて、空気流路を流れる空気の流量を測定するものである。
なお、以下の説明では、絶縁膜２の表面３に平行で、かつ空気の流れと直交する方向を長手方向と定義して説明する。 The flow rate measuring device 1 includes an insulating film 2 provided in a plane substantially parallel to the air flow in the air flow path, a heating resistor 4 provided on the surface 3 of the insulating film 2 and generating heat when energized, and generating heat on the surface 3. Provided on the downstream side of the resistor 4, the electrical resistance changes according to the temperature, and includes downstream detection resistors 5 and 6, and the air is detected based on the detection difference between the upper and downstream detection resistors 5 and 6. The flow rate of air flowing through the flow path is measured.
In the following description, the direction parallel to the surface 3 of the insulating film 2 and perpendicular to the air flow is defined as the longitudinal direction.

絶縁膜２は、空気流路内に空気の流れと略平行に配された基板９の表面上に形成されている。そして、絶縁膜２の表面３に、発熱抵抗４と上、下流側検出抵抗５、６とが設けられ、発熱抵抗４および上、下流側検出抵抗５、６は保護膜１０により覆われている。なお、絶縁膜２の裏側には、基板９と発熱抵抗４および上、下流側検出抵抗５、６とを熱的に絶縁するための空洞１１が形成されている。   The insulating film 2 is formed on the surface of the substrate 9 disposed substantially parallel to the air flow in the air flow path. A heating resistor 4 and upper and downstream detection resistors 5 and 6 are provided on the surface 3 of the insulating film 2, and the heating resistor 4 and the upper and downstream detection resistors 5 and 6 are covered with a protective film 10. . A cavity 11 for thermally insulating the substrate 9 from the heating resistor 4 and the upper and downstream detection resistors 5 and 6 is formed on the back side of the insulating film 2.

発熱抵抗４は、１つの抵抗体から形成されており、長手方向に１回折り返されたＵ字形状を呈している。そして、発熱抵抗４は、後述する検出領域１２を加熱するための発熱領域１３を表面３上に形成している。また、発熱領域１３は矩形状であり、発熱抵抗４の電位端１６、１７は、発熱領域１３の長手方向の一端縁１８に配されている。なお、電位端１６、１７には、外部回路と接続するための端子１９、２０が接続している。   The heating resistor 4 is formed of a single resistor and has a U-shape that is folded once in the longitudinal direction. The heat generating resistor 4 forms a heat generating region 13 on the surface 3 for heating a detection region 12 described later. Further, the heat generating region 13 has a rectangular shape, and the potential ends 16 and 17 of the heat generating resistor 4 are arranged at one end edge 18 in the longitudinal direction of the heat generating region 13. The potential terminals 16 and 17 are connected to terminals 19 and 20 for connection to an external circuit.

上、下流側検出抵抗５、６は、長手方向に互いに平行に設けられおり、表面３上で上、下流側検出抵抗５、６で挟まれて区画される矩形の領域が、検出差分を検出するための検出領域１２をなし、発熱領域１３により加熱される。   The upper and downstream detection resistors 5 and 6 are provided in parallel to each other in the longitudinal direction, and a rectangular area defined by being sandwiched between the upper and downstream detection resistors 5 and 6 on the surface 3 detects a detection difference. The detection area 12 is formed and heated by the heat generation area 13.

上流側検出抵抗５は、発熱抵抗側の抵抗体２３と反発熱抵抗側の抵抗体２４とから形成される。抵抗体２３は、電位端２５、２６が検出領域１２の他端縁２８から引き出されており、検出領域１２の一端縁２７で２回の折り返しを有し、他端縁２８で１回の折り返しを有している。抵抗体２４は、電位端３１、３２が検出領域１２の一端縁２７から引き出されており、検出領域１２の他端縁２８で２回の折り返しを有し、一端縁２７で１回の折り返しを有している。
また、下流側検出抵抗６も、発熱抵抗側の抵抗体３３と反発熱抵抗側の抵抗体３４とから形成されており、抵抗体３３は抵抗体２３と同様の構成であり、抵抗体３４は抵抗体２４と同様の構成となっている。 The upstream side detection resistor 5 is formed of a resistor 23 on the heating resistor side and a resistor 24 on the counter heating resistor side. In the resistor 23, the potential ends 25 and 26 are drawn from the other end edge 28 of the detection region 12, and have one turn at the one end edge 27 of the detection region 12, and one turn at the other end edge 28. have. In the resistor 24, the potential ends 31 and 32 are drawn from the one end edge 27 of the detection region 12, have two turns at the other end edge 28 of the detection region 12, and have one turn at the one end edge 27. Have.
The downstream detection resistor 6 is also formed of a resistor 33 on the heat generating resistor side and a resistor 34 on the counter heat generating resistor side, and the resistor 33 has the same configuration as the resistor 23. The configuration is the same as that of the resistor 24.

すなわち、抵抗体２３の電位端２５、２６および抵抗体３３の電位端３７、３８は、検出領域１２の他端縁２８から引き出されており、抵抗体２４の電位端３１、３２および抵抗体３４の電位端３９、４０は、検出領域１２の一端縁２７から引き出されている。そして、上流側検出抵抗５の電位端２５、２６、３１、３２、および下流側検出抵抗６の電位端３７〜４０には、外部回路と接続するための端子４１〜４８が接続している。   That is, the potential ends 25 and 26 of the resistor 23 and the potential ends 37 and 38 of the resistor 33 are drawn from the other end edge 28 of the detection region 12, and the potential ends 31 and 32 of the resistor 24 and the resistor 34 are extracted. The potential ends 39 and 40 are drawn from one end edge 27 of the detection region 12. Terminals 41 to 48 for connecting to an external circuit are connected to the potential ends 25, 26, 31 and 32 of the upstream detection resistor 5 and the potential ends 37 to 40 of the downstream detection resistor 6.

〔実施例１の特徴〕
次に、流量測定装置１の特徴を図１を用いて説明する。
実施例１の流量測定装置１では、発熱領域１３の長手方向の一端縁１８と他端縁５１との距離Ｌ０、および、上、下流側検出抵抗５、６の長手方向の長さの１／２の位置５２と一端縁１８との距離Ｌ１が数式１を満たす。これにより、発熱領域１３の一端縁１８が、検出領域１２の一端縁２７よりも一端側に突出している。
さらに、発熱抵抗４の上流側と下流側との温度差が最高になる長手方向の位置５３と一端縁１８との距離Ｌ２は、距離Ｌ１と同一である。つまり、長手方向において、位置５２、５３は一致している。 [Features of Example 1]
Next, features of the flow rate measuring device 1 will be described with reference to FIG.
In the flow measurement device 1 of the first embodiment, the distance L0 between the one end edge 18 and the other end edge 51 in the longitudinal direction of the heat generating region 13 and the length in the longitudinal direction of the upper and downstream detection resistors 5 and 6 are 1 /. The distance L1 between the position 52 of 2 and the one end edge 18 satisfies Expression 1. As a result, the one end edge 18 of the heat generating region 13 protrudes to the one end side from the one end edge 27 of the detection region 12.
Further, the distance L2 between the longitudinal position 53 where the temperature difference between the upstream side and the downstream side of the heating resistor 4 becomes the highest and the one end edge 18 is the same as the distance L1. That is, the positions 52 and 53 coincide in the longitudinal direction.

〔実施例１の効果〕
実施例１の流量測定装置１では、電位端１６、１７が配される発熱領域１３の一端縁１８を検出領域１２の一端縁２７よりも長手方向の一端側に突出させることで、発熱領域１３の内で温度分布の形成が不明確な電位端１６、１７近傍を検出領域１２から除外している。これにより、発熱領域１３の内で温度分布の形成が明確な領域のみを検出領域１２に含ませることができるので、流量検出感度を高めることができる。 [Effect of Example 1]
In the flow rate measuring device 1 of the first embodiment, the one end edge 18 of the heat generating region 13 where the potential ends 16 and 17 are arranged protrudes from the one end edge 27 of the detection region 12 to one end side in the longitudinal direction. Among these, the vicinity of the potential ends 16 and 17 where the formation of the temperature distribution is unclear is excluded from the detection region 12. Thereby, since only the area | region where formation of temperature distribution is clear in the heat_generation | fever area | region 13 can be included in the detection area | region 12, flow volume detection sensitivity can be improved.

また、数式１を満たすように発熱領域１３と検出領域１２とを設ければ、上、下流側検出抵抗５、６の検出差分に基づいて算出される長手方向の平均温度差を５０℃以上にすることができる（図２参照）。このため、流量検出感度を確実に高めることができる。
さらに、数式１を満たす距離Ｌ１が距離Ｌ２と同一となるように発熱領域１３と検出領域１２とを設ければ、上、下流側検出抵抗５、６の検出差分に基づいて算出される長手方向の平均温度差を最大値ＭＡＸに略一致させることができる（図２参照）。このため、流量検出感度を最大限に高めることができる。 Further, if the heat generation region 13 and the detection region 12 are provided so as to satisfy Formula 1, the average temperature difference in the longitudinal direction calculated based on the detection difference between the upper and downstream detection resistors 5 and 6 is 50 ° C. or more. (See FIG. 2). For this reason, the flow rate detection sensitivity can be reliably increased.
Furthermore, if the heat generation region 13 and the detection region 12 are provided so that the distance L1 satisfying Equation 1 is the same as the distance L2, the longitudinal direction calculated based on the detection difference between the upper and downstream detection resistors 5 and 6 Can be made to substantially coincide with the maximum value MAX (see FIG. 2). For this reason, the flow rate detection sensitivity can be maximized.

〔参考例〕
参考例の流量測定装置１の構成を、図３を用いて説明する。
参考例の流量測定装置１によれば、抵抗体２３、３３は、抵抗体２４、３４と同様に、電位端２５、２６および電位端３７、３８が検出領域１２の一端縁２７から引き出されており、検出領域１２の他端縁２８で２回の折り返しを有し、一端縁２７で１回の折り返しを有している。すなわち、上流側検出抵抗５の電位端２５、２６、３１、３２、および下流側検出抵抗６の電位端３７〜４０は、すべて、検出領域１２の長手方向の一端縁２７から引き出されている。 [Reference example]
The configuration of the flow measurement device 1 of the reference example will be described with reference to FIG.
According to the flow rate measuring device 1 of the reference example , the resistors 23 and 33 have the potential ends 25 and 26 and the potential ends 37 and 38 drawn out from the one end edge 27 of the detection region 12, similarly to the resistors 24 and 34. In addition, the other end 28 of the detection region 12 has two turns and the one end 27 has one turn. That is, the potential ends 25, 26, 31, and 32 of the upstream detection resistor 5 and the potential ends 37 to 40 of the downstream detection resistor 6 are all drawn from one end edge 27 in the longitudinal direction of the detection region 12.

ここで、発熱抵抗４から検出領域１２に与えられる熱は、上、下流側検出抵抗５、６にも熱伝導で伝わるため、上流側検出抵抗５の電位端２５、２６、３１、３２に接続する端子４１〜４４、および下流側検出抵抗６の電位端３７〜４０に接続する端子４５〜４８も放熱先となる。そこで、上流側検出抵抗５の電位端２５、２６、３１、３２、および下流側検出抵抗６の電位端３７〜４０を一端縁２７のみから引き出すことで、一端縁２７および他端縁２８の両方から引き出す場合よりも、上、下流側検出抵抗５、６の端子４１〜４８への放熱量を少なくすることができる。このため、温度分布をより明確に形成することができるので、流量検出感度をさらに高めることができる。   Here, since the heat given from the heating resistor 4 to the detection region 12 is also transferred to the upper and downstream detection resistors 5 and 6 by heat conduction, it is connected to the potential ends 25, 26, 31 and 32 of the upstream detection resistor 5. The terminals 41 to 44 to be connected and the terminals 45 to 48 connected to the potential ends 37 to 40 of the downstream detection resistor 6 are also heat radiation destinations. Therefore, by pulling out the potential ends 25, 26, 31, 32 of the upstream detection resistor 5 and the potential ends 37 to 40 of the downstream detection resistor 6 from only one end edge 27, both the one end edge 27 and the other end edge 28 are extracted. The amount of heat released to the terminals 41 to 48 of the upstream and downstream detection resistors 5 and 6 can be reduced as compared with the case of drawing out from. For this reason, since the temperature distribution can be formed more clearly, the flow rate detection sensitivity can be further increased.

〔変形例〕
実施例１によれば、距離Ｌ１は距離Ｌ２と同一であったが、距離Ｌ１は距離Ｌ２と同一でなくても、数式１を満たしていれば、上、下流側検出抵抗５、６の検出差分に基づいて算出される長手方向の平均温度差を５０℃以上にすることができる。さらに、距離Ｌ１が数式１を満たしていなくても、発熱領域１３の一端縁１８が検出領域１２の一端縁２７よりも一端側に突出していれば、少なくとも、温度分布の形成が不明確な電位端１６、１７近傍を検出領域１２から除外して検出できるため、流量検出感度を高めることができる。
また、実施例１および参考例によれば、発熱抵抗４はＵ字形状を呈していたが、抵抗体２３、２４、３３、３４のように、３回以上の奇数回の折り返しを有する形状としてもよい。 [Modification]
According to the first embodiment, the distance L1 is the same as the distance L2. However, even if the distance L1 is not the same as the distance L2, the upper and downstream detection resistors 5 and 6 are detected as long as Formula 1 is satisfied. The average temperature difference in the longitudinal direction calculated based on the difference can be 50 ° C. or more. Furthermore, even if the distance L1 does not satisfy Formula 1, as long as the one end edge 18 of the heat generating region 13 protrudes to the one end side from the one end edge 27 of the detection region 12, at least a potential with which the formation of the temperature distribution is unclear. Since the vicinity of the edges 16 and 17 can be detected by being excluded from the detection region 12, the flow rate detection sensitivity can be increased.
Moreover, according to Example 1 and the reference example , although the heating resistor 4 was U-shaped, the resistor 23, 24, 33, 34 has a shape having an odd number of turns of three times or more. Also good.

（ａ）は流量測定装置の構成図であり、（ｂ）は（ａ）のＡ−Ａ断面図である（実施例１）。(A) is a block diagram of a flow measurement apparatus, (b) is AA sectional drawing of (a) (Example 1). 上、下流側検出抵抗の検出差分に基づいて測定される平均温度差と、Ｌ１／Ｌ０との関係を示す相関図である（実施例１）。(Example 1) which is a correlation diagram which shows the relationship between the average temperature difference measured based on the detection difference of the upper and downstream detection resistance, and L1 / L0. 流量測定装置の構成図である（参考例）。It is a block diagram of a flow measuring device ( reference example ). 流量測定装置の構成図である（従来例）。It is a block diagram of a flow measuring device (conventional example).

１ 流量測定装置
２ 絶縁膜
３ 表面
４ 発熱抵抗
５ 上流側検出抵抗
６ 下流側検出抵抗
１２ 検出領域
１３ 発熱領域
１６、１７ 発熱抵抗の電位端
１８ 発熱領域の一端縁
２５、２６、３１、３２ 上流側検出抵抗の電位端
３７〜４０ 下流側検出抵抗の電位端
２７ 検出領域の一端縁
２８ 検出領域の他端縁
５１ 発熱領域の他端縁
５２ 上、下流側検出抵抗の長手方向の長さの１／２の位置
５３ 発熱抵抗の上流側と下流側との温度差が最高になる長手方向の位置 DESCRIPTION OF SYMBOLS 1 Flow measurement apparatus 2 Insulating film 3 Surface 4 Heating resistance 5 Upstream detection resistance 6 Downstream detection resistance 12 Detection area 13 Heating area 16, 17 Potential end 18 of heating resistance One end edge 25, 26, 31, 32 of heating area Upstream Potential end 37 to 40 of the side detection resistor Potential end 27 of the downstream detection resistor One end edge of the detection region
28 On the other end edge 51 of the detection area 51 On the other end edge 52 of the heat generation area, a position that is 1/2 of the length in the longitudinal direction of the downstream detection resistance 53 The temperature difference between the upstream side and the downstream side of the heat generation resistance becomes the highest Longitudinal position

Claims (2)

空気流路に空気の流れと略平行な平面状に設けられる絶縁膜と、前記絶縁膜の表面に設けられて通電により発熱する発熱抵抗と、前記絶縁膜の表面で前記発熱抵抗の上流側に設けられ、温度に応じて電気抵抗が変化する上流側検出抵抗と、前記絶縁膜の表面で前記発熱抵抗の下流側に設けられ、温度に応じて電気抵抗が変化する下流側検出抵抗とを備え、前記上流側検出抵抗と前記下流側検出抵抗との検出差分に基づいて、前記空気流路を流れる空気の流量を測定する流量測定装置において、
前記絶縁膜の表面に平行で、かつ空気の流れと直交する方向を長手方向と定義すると、前記上流側検出抵抗および前記下流側検出抵抗は、前記長手方向に互いに平行に設けられ、前記絶縁膜の表面上で前記上流側検出抵抗と前記下流側検出抵抗とで挟まれて区画される領域は、前記検出差分を検出するための検出領域をなし、前記上流側検出抵抗および前記下流側検出抵抗の電位端が、前記検出領域の長手方向の両端縁から引き出され、前記発熱抵抗は、前記絶縁膜の表面上に前記検出領域を加熱するための発熱領域を形成し、前記発熱領域の前記長手方向の一端縁のみに、前記発熱抵抗の電位端が配され、前記発熱領域の前記長手方向の一端縁が、前記検出領域の前記長手方向の一端縁よりも一端側に突出し、
前記発熱抵抗の他端縁を前記検出領域の他端縁よりも一端側に配置することにより、前記発熱抵抗の上流側と下流側との温度差が最高になる前記長手方向の位置が、前記検出領域の長手方向の中央付近に位置して、前記発熱領域の前記長手方向の一端縁と他端縁との距離Ｌ０、ならびに、前記上流側検出抵抗および前記下流側検出抵抗の前記長手方向の長さの１／２の位置と前記発熱領域の前記長手方向の一端縁との距離Ｌ１は、以下の相関式を満たすことを特徴とする流量測定装置。
５４／１００≦Ｌ１／Ｌ０≦８１／１００ An insulating film provided in a plane substantially parallel to the air flow in the air flow path, a heat generating resistor provided on the surface of the insulating film and generating heat when energized, and upstream of the heat generating resistor on the surface of the insulating film And an upstream detection resistor whose electrical resistance changes according to temperature, and a downstream detection resistor which is provided downstream of the heat generation resistor on the surface of the insulating film and whose electrical resistance changes according to temperature. In the flow measurement device for measuring the flow rate of the air flowing through the air flow path based on the detection difference between the upstream detection resistor and the downstream detection resistor,
When a direction parallel to the surface of the insulating film and perpendicular to the air flow is defined as a longitudinal direction, the upstream detection resistor and the downstream detection resistor are provided in parallel to each other in the longitudinal direction, and the insulating film An area between the upstream detection resistor and the downstream detection resistor that is partitioned by the upstream detection resistor forms a detection region for detecting the detection difference, and the upstream detection resistor and the downstream detection resistor And the heating resistor forms a heating region for heating the detection region on the surface of the insulating film, and the longitudinal end of the heating region is formed in the longitudinal direction of the detection region. A potential end of the heat generating resistor is arranged only at one end edge in the direction, and one end edge in the longitudinal direction of the heat generating region protrudes to one end side from one end edge in the longitudinal direction of the detection region,
By disposing the other end edge of the heating resistor on one end side with respect to the other end edge of the detection region, the position in the longitudinal direction where the temperature difference between the upstream side and the downstream side of the heating resistor is maximized is Located near the center in the longitudinal direction of the detection area, the distance L0 between the one end edge and the other end edge in the longitudinal direction of the heat generation area, and the upstream detection resistance and the downstream detection resistance in the longitudinal direction. A distance L1 between a half position of the length and one end edge in the longitudinal direction of the heat generating region satisfies the following correlation equation.
54/100 ≦ L1 / L0 ≦ 81/100 請求項１に記載の流量測定装置において、前記発熱抵抗の上流側と下流側との温度差が最高になる前記長手方向の位置と前記発熱領域の前記長手方向の一端縁との距離Ｌ２は、前記距離Ｌ１と同一であることを特徴とする流量測定装置。   2. The flow rate measurement device according to claim 1, wherein a distance L <b> 2 between the position in the longitudinal direction where the temperature difference between the upstream side and the downstream side of the heating resistor is the highest and one end edge in the longitudinal direction of the heating region is The flow rate measuring device, which is the same as the distance L1.
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JP3364115B2 (en) * 1997-07-03 2003-01-08 三菱電機株式会社 Thermal flow detection element
JP3981907B2 (en) 1998-10-21 2007-09-26 株式会社デンソー Flow measuring device
KR100499227B1 (en) * 2000-05-02 2005-07-01 가부시키 가이샤 히다치 카 엔지니어링 Device for measuring physical quantity, method of manufacture thereof, and vehicle control system using device for measuring physical quantity
JP3971920B2 (en) 2001-12-04 2007-09-05 日本特殊陶業株式会社 Flow characteristic measuring element and manufacturing method thereof
JP2004361271A (en) * 2003-06-05 2004-12-24 Hitachi Ltd Thermal type air flowmeter
JP4966526B2 (en) * 2005-09-07 2012-07-04 日立オートモティブシステムズ株式会社 Flow sensor

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